What's Killing the "Killer"
Since the age of five I have always known what I wanted to do with my life: to get my degree in marine biology and become the leading field researcher on orcas. Ok, I know the leading researcher is a little far fetched, but a girl can dream right? I dreamt of spending hours in the open ocean conducting research studies on behavior, social interaction, migratory patterns, and more. Unfortunately, in the field of marine biology, it looks like by the time I graduate, these topics will be the least of interest. Most important to researchers right now is what is causing the death of orcas. Orcinus orca, the "killer whale" is a toothed whale found in the oceanic dolphin family. Most people know orcas as "FREE WILLY". Something is killing these animals and we need to figure out what it is and fast. The two most common and researched hypothesis are 1. Naval sonar research and 2. Water pollutants. There is a lot of controversy on sonar research and its effects on wildlife. Water pollutants on the other hand are pretty much accepted across the board. With orcas being apex predators they get second hand pollutants from the fish and marine mammals that they eat. However, there is a new emerging theory on the deaths of the killer whale that is gaining world wide attention and it involves airborne microbes.
The Research
Thanks to researchers at the University of Washington and Global Research and Rescue, a new way of thinking about orca health is in motion. Studies are being carried out to analyze the content of exactly what is in killer whales lungs. In the study "Investigation into the Microbial Culture and Molecular Screening of exhaled breaths of Endangered Southern Resident Killer Whales (SRKW) and Pathogen Screening of the Sea Surface Microlayer (SML) in Puget Sound" a pod of orcas were tracked and a pole with petri dishes attached at the end was used to capture the breath of the orcas when they surfaced. From this researchers have been able to analyze what the orcas are breathing. [Read original article here]
The plates (modified to be covered until the time of collection and closed immediately post
collection) include: two sterile plates with no media, a blood agar plate, a salt enriched
trypticase soy agar (TSA) plate, and a Sabouraud (SAB) media plate.
Why this matters
Within the last few years genetic sampling has been done on a wide variety of orcas. It has been determined that there are actually several species of orcas. By breaking this once large group of animals into smaller groups, certain species are now found to be a lot more rare than previously thought. While a group of orcas known as the "puget sound orcas", found in Puget Sound, Washington many months of the year, have not been considered threatened or endangered, with the current threats of pollution on its population, it is only a matter of time.
The research done by professors at the University of Washington and Global Reasearch and Rescue, suggests that not is water pollution affecting the marine life, but also airborne pollution. These diseases that are now floating around in the air are much more dangerous to the marine life than to humans. When a human inhales and exhales, we exchange about 20% of what is in our lungs. Compare this to an orca who is thought to exchange around 70% of what is in its lung in a single breath. Orcas are the perfect model for this research on airborne pollutants because they are literally found in every ocean. This gives us the opportunity to look at these animals and to see the bigger picture of everything that is happening in the marine ecosystems.
Although it is good that the issue of airborne pollutants on orcas is finally getting some press attention, this isn't the first research or account of these issues. Puget Sound Orcas, one of the few groups of orcas that is protected and considered threatened by the local government (although they are not classified threatened by the IUCN Redlist), have been known to have problems due to local air quality. "It's no secret that a stew of microbes from land regularly invades Puget Sound. Bacteria and nutrients from humans and animals have for decades been funneled into estuaries and bays, causing oxygen problems in Hood Canal and resulting in shellfish-bed closures". [Read more about the pollution in Puget Sound] Puget Sound Orcas are residential, meaning that they tend to stay closer to land and prey on fish rather than the transient orcas that stay further out to sea and prey on marine mammals. Below you can see their geographical range and how close to land these orcas stay. For any residential pod, this is a deathly combination because now they are getting pollutants in their water, food, and air.
The figure above shows the slight decline of the Puget Sound Orcas population over the more recent years. With these facts and figures, Puget Sounds make the perfect model to study the effects of pollutants on the decline of population in marine life.
How does this effect the rest of the marine life?
The new discovery of these land bacteria, fungi and viruses found in orcas is already starting to reach a broader scope in the science community. It has recently been confirmed that the air pollutants that these orcas are breathing are directly having an effect on the pollution of the water itself. [Read about air pollutants effects on water pollution] These air pollutants will eventually land on the water surface and form a very thin film known as the sea-surface micro-layer. Therefore, this becomes a much bigger issue extending to other things in the ocean that occupy the same range as the orcas. As mentioned in "Investigation into the Microbial Culture and Molecular Screening of exhaled breaths of Endangered Southern Resident Killer Whales and Pathogen creening of the Sea Surface Microlayer in Puget Sound", orcas can be a good indicator of biological integrity and marine environmental quality. By using them as a model we can study the effects of air pollutants on the marine ecosystems.Rethinking Research
From this study, it can be seen that we need to take a broader look what is killing marine mammals and not limiting our thinking to things such as water pollution and sonar research. The fact that pneumonia, normally found only on land has been found in half of the 46 washed up or stranded orcas is a clear indicator that something else is going on. This is not to say that pneumonia or the other things being found in the lungs of orcas is the cause of the death in these killer whales, but it is at least is a factor to consider in looking at things such as a weakened immune system that could then lead to the death of these mammals from other things such as water pollutants.
Links and Credit Images:
Images (In order of Appearance)
[Image Credit: PETE SCHROEDER]
[Image Credit: PETE SCHROEDER]
[Image Credit: PETE SCHROEDER]
References (In alphabetical order):
Essington, T. Klinger, T. Conway-Cranos, T. Buchanan, J. James, A. Kershner, J. Logan, I. West, J. (March, 2011) Biophysical Condition of Puget Sound. Retrieved May 25, 2012, from
Foote, A. Vilstrup, J. DeStephanis, R. Verborgh, P. Abel Neilsen, S. Deavile, R. Kleivane, L. Martin, V. Miller, P. Oixn, N. Perez-gil, M. Rasmussen, M. Reid, R. Robertson, K. Rogan, E. Simila, T. Tejedor, M. Vester, H. Vikingsson, G. Willerslev, E. (Februrary, 2011) Genetic differentiation among North Atlantic killer whale populations. Retrieved May 25, 2012, from
http://web.ebscohost.com.libproxy.uoregon.edu/ehost/pdfviewer/pdfviewer?sid=cef1e320-afa8-482d-844d-2c85059c34e0%40sessionmgr112&vid=2&hid=119
Genome Research. Killer Whales are probably several different species. Retrieved May 25, 2012, from
Mountain, M. (April 2012) Orcas Now Being Poisoned by Air They Breathe. Retieved May 25, 2012, from
http://www.zoenature.org/2012/04/orcas-now-being-poisoned-by-air-they-breathe/
Schroeder, P. Raverty, S. Zebek, E. Cameron, D. Eshghi, A. Bain, D. Wood, R. Rhodes, L. Handson, B. Investigation into the Microbial Culture and Molecular Screening of exhaled breaths of Endangered Southern Resident Killer Whales (SRKW) and Pathogen Screening of the Sea Surface Microlayer (SML) in Puget Sound. Retrieved May 25, 2012, from
http://grrescue.org/Research%20library%20files/GRRBACTNWFSC2009FieldSeasonReportDoc1correc/GRRBACTNWFSC2009FieldSeasonReportDoc1correc.pdf
Welch, C. (April 2012) Killer Whales Facing an Airborne Threat. Retrieved May 25, 2012, from
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